Well cementing composition



, United States Patent (ca/v 4%) 2,798,003 Patented July 2, 1957 cember 27, 1938, and the compounds described by Mark 2 798 003 in U. S. Patent 2,141,570, dated December 27 1938.

WELL CEMENTING COMPOSITION Bryan E. Morgan and George K. Dumbauld, Houston, Tex., assignors, by mesne assignments, to Esso Research and Engineering Company, Elizabeth, N. J., a corporation of Delaware No Drawing. Application April 25, 1955, Serial No. 503,782

11 Claims. (Cl. 106-90) The present invention is directed to a cement composition. More particularly, the invention is directed to a cement composition adapted for use in oil wells and. particularly a composition which develops a low strength on setting. In its more specific aspects, the invention-is directed'to a cement composition for use in oil wells and a method of preparing same.

This application is a continuation-in-part of Serial No. 421,432 filed April 6, 1954, entitled Well Cementing Composition and Method of Using Same which is a continuation-in-part of Serial No. 267,922 entitled Well Cementing Composition and Method of Preparing Same" filed January 23, 1952, for Bryan E. Morgan and George Dumbauld, now abandoned.

The present invention may be described briefly as involving a cement composition adapted for use in well cementing operations which comprises a, Portland cement, a liquid hydrocarbon, a watewmrganic 5 I acids. Tucker The compounds of the Tucker patent, supra, are soluble salts of the sulfonic acids, such as a romatic sulfonic sc oses that these compounds are formed bif'causing an aromatic sulfonic acid to react, with formaldehyde or imm wo mdles o sulfonic acid to each mole of aldehyde. Tucker then forms the water soluble salts of these compounds such as the sodium salts. It is also contemplated that the compounds of Mark, supra, may be used such as exemplified by Mark on page 2 of his specification where he sets out the derivatives of lignin. It is intended that the organic dispersing agant will include all of the compounds mentioned by Mark and Tucker, supra. We also.

diipersing agent and a sufiicient amount 0 waiito" pro vfde a pumpable slurry when the components of the composition are admixed.

The cement used in our composition is Portland cement as described and specified in A. S. T. M. Designation: C-150. Such Portland cements are well known and readily available on the market.

The liquid hydrocarbon employed in our improved compositiodshould have" a viscosity below about 40 centipoises at 100 F., because hydrocarbons of high viscosity are generally heavier and are more dilficult to emulsify. Preferably, the viscosity of the hydrocarbon should be below about 10 centipoises at 100 F. The liquid hydrocarbon may be a pure hydrocarbon or it may be a mixture of hydrocarbons. The liquid hydrocarbon may be a crude petroleum or it may be a fraction of crude petroleum, such a s'a gasoline, a kerosene, a gas oil or a diesel oil fraction. It may be desirable to use crude petroleum such as is found in adjacent oil wells in the field where the cementing operation is conducted or under some conditions it may be desirable to use a fuel oil which may be a kerosene or a diesel oil.

The liquid hydrocarbon, as described, may be employed in an amount in the range between about 15 cc. and about 60 cc. per 100 grams of dry cement. A preferred amount is in the range of 20 cc. to 40 cc. per 100 grams of the dry cement.

The water solubleorganic dispersing agent ma be any water solu u age'ntsfandthe fifeareggeq a As examples of the sulfonated compounds be mentioned a su1tgn a tgd ondensationproduct, such as disdi aents for use in our inventi fying agents l'l: I hydrophilic and lipophilic The emulsin our invention are the polar, non-ionic compoundsand the cationic' 'alkyl substituted quaternary ammonium salts EXAMINER These polar emulsifying compounds are of the este I ether-alcohol, ether-ester type. As examples of the emultioned sorbitan mono-laurate, a condensation product of ethylene oxide, propylene 'oxide, and ro lene polyoxyethylene lauryl alcohol, polyoxyethyleneoctyl phenol, and the like. Also we may use cety net y annrronium chloride as well as other alkyl substituted quaternary ammonium salts such as cetyl dimethyl ammonium bromide.

While we have given numerous examples of our organic dispersing agent, it will be clear to the skilled workman that many compounds satisfying the requirement of being calcium tolerant may be used in lieu of the specific materials enumerated above.

The organic dispersing agent of the type illustrated may be used in an amount in the range between 0 and 1.0% by weight based on the dry cement. A preferred amount 18 in the range from 0.2% to 0.6% by weight.

The water should be employed in our improved composition in an amount sufiicient to provide a JEBD -me slurry. An amount in the range between 0 I l! by we ght based on the dry cement will ordinarily be satisfactor'y with a preferred range from 60% to by weight.

The preparation of our improved composition may be accomplished in several difierent ways. One method of forming a slurry in accordance with our composition which is adapted for use in well cementing operations is to make an emulsion of the water and the l iquid.hydrocarbon and thereafter admix wifh'said emulsion a blend of the Portland cement and a water-soluble organic dispersing agent, the proportions of the water, hydrocarbon, and dispersing agent being in the ranges given above.

Another method of forming our improved composition may be employed and this comprises admixing water, a liquid hydrocarbon and a water soluble organic dispersing agent to form an emulsion, the water soluble organic dispersing agent serving as an emulsifying agent. Portland cement is then admixed with the emulsion to form our composition.

The composition of the present invention may also be formedbyblendingP '7 0 le organic dispelsweat in an amount in the range be tween 0.1% and 1.0% by weight based on the dry cement.

x \clo se d in Serial No. 09,510, filed February 5, 1951, in

the name of Richard A. Salathiel,

" 'acrilpgbyjlheker'in U. S. Patent 2,1 dated The Portland cement and the organic dispersing agent are then admixed with water in an amount in the range between 50 and by weight based on the dry cement to form a slurry. Liquid hydrocarbon is then admixed with the slurry in an amount in the range between 15 cc. and 60 cc. per 100 grams of the dry cement.

It is also desirable in some instances to add to our composition a small amount of a The amount of the colloidal clay should be'small since if large amounts are used it may be necessary either to decrease unduly the amount of the liquid hydrocarbon or to increase unduly the amount of the water included in the composition. The colloidal clay ordinarily should be employed in an amount no greater than about by weight based on the dry cement. An amount from about 1% to about 5% by weight based on the dry cement may be used. As examples of suitable colloidal clays are those sush as w nabemo ts P magnetism, and those clays including the montmorillonite: and particularly the aodiurp montmorillqnite The calcium montmorillonite may be employed and suitable other salts of the montmorillonites may be used. The sodium montmorillonites, such as those encountered in Wyoming bentonite, are included in the preferred type of clay. Clays falling within the purview of our invention are described in the Carman patent, 1,460,788, and the Harth patent, 1,991,637.

When a colloidal clay of the type exemplified above is employed in our composition, the composition may be formed by any of the methods described above in which the clay has been blended with the dry cement prior to forming the slurry or it may be formed in the following manner:

The liquid hydroca n or ii com one position may e emulsified with water either in the prese' H n m ,such as To this emulsioii may be 4 used in preparing our composition, it is to be understood that vigorous agitation is to be used to obtain intimate admixture of the composition.

Illustrative of slurries embraced by our invention are In order to illustrate the invention further a number of stable oil-in-water type cement emulsionslurrjes were preparedmao'idance Wltfi 5111 iiiv'e ntion such that the slurries possessed suitable fluidity for pumping into boreholes, such as oil wells. The slurries were formed by three different methods. In the firstmethod water and oil were emulsified by violent agitation, calcium lignosulfonate was added ,as an organic dispersing agent to dry cement and the resulting mixture was added to the emulsion with stirring. In the second method calcilu li nosulfonate as an organic (1' 'ng agent was mixed wiili dry cemenf, The mixture was added to water with stirring, and oil was added to the slurry formed thereby. In the third method an emulsion of water, oil and calcium lignisulfonate was prepared and dry cement added thereto.

The proportions of the ingredients of the several cement slurries, the method of forming the slurries and the inspections and observations of the physical characteristics of the slurries are given in Table II, which illustrates the effect of varying composition and mixing procedures on the properties of the emulsion cement slurries.

Table II EFFECT OF LIQUID CONTENT WITH WATER-TO-OIL RATIO OF 2:1

Composition of Emulsion Cement Slurry Fluldlty Method at R. P. M. at Observa- Calclum Mixing 1 400 grams tions on Remarks Portland Cement, Llgno Water, 011. Stormer Setting grams lultonate. cc. cc. 4

100 1.0 m 80 A 840 Set No oil separated. 100 1.0 85 A 1,090 Set--.-- Do.

EFFECT OF OIL CONTENT AT CONSTANT WATER-TO-CEMENT RATIO 70 26 A 1,250 Set..--. No oil separated. 70 85 A 1.090 Set D0. 70 42 A 800 Set...... D0.

t m r-t rr- OOQQQQQ no A 840 Set..---- No oil separated. co 80 B 830 mt Do. 70 A 1. 090 wt Do. 70 85 B 1, 220 D0. 70 Q A 800 bet Do 70 42 B 480 Set Do. 70 42 C 1, 000 Set-. Do.

1 Kerosene. speclflc gravity 010.83. viscosity of 1.6 centipoises. A-Emuislon of water and 0!! prepared by violent agitation. Calcium lignosulfonate mixed with dry cement and resulting mixture Placed in emulsion with stirring.

need In water with stirring. Oil a dad to above slurry. C-Emulsion of water, um llgnosulfonate prepared and dry cement added.

cement and resulting mixture p oil, and calci B-Calcium lignosullonate mixed with i Specimens cured under water F.

It will be noted from the data shown in Table II that in all instances the cement slurries possessed fluidi-ties suitable for pumping and they set without any separation 0 or Additional slurries were then made up to illustrate the effect of change in oil content and the addition of bentonite on the physical properties of the slurry and of the set cement. These data area presented in Table III which sets out the fluidity, the filtration, thickening time, and

' strength properties of satisfactory cement compositions prepared in accordance with our invention.

Table III Composition oi Emulsion Cement Blurry Filtration Tensile Strength:

Fluidity- Water Loss at 100 Thickening ibalsq. in.-Cured R. P. M. at lbs/sq. 111., cc. Time 1 Under Water at Calcium 400-grams 120 F.

Portland Cement, Benton- Llgno- Water, Otl' Stormer grams ite, gram sulfonate, cc. cc.

grams 3min. 30min. Hrs. Mina. lday lode 0 0.4 60 0 1, 430 0 0. 4 60 700 103 250 0 0. 4 e0 550 53 152 4 0. 4 -70 0 1, 430 4 0.4 70 an 780 29 102 113 940 4 0.4 70 30 100 0 0. 4 60 30 670 112 1 113 197 4 0. 4 11 970 27 96 2 10 1 Tested in Standard A. P. I. iowressure wall building mud tester.

I Tested in accordance with Sch ule 8, wellsimulation casing-cement job for 14,000 it. depth, A. P. 1. Code 82 (Tentative),

Second Edition. June. 1950.

i K osene specific gravity of 0.80, viscosity of 1.6 centipolsea. 4 0 er rand of Portland cement used for these tests.

It will be noted from the data in Table III that an 20 the presence of oil in the filtrate from the slurry. This increase in the oilcontgntjecreases the fiudity otthe s urry. amoun o 01 e re uces the filtration rate and increases slightly the thickening time of the cement slurry without afiecting appreciably the tensile strength of the set cement. It will be noted that suflicient tensile strength was developed both with and without bentonite in the slurry to give a cement of satisfactory strength for oil well cementing operations.

In order to illustrate the sup oved cementing composition over ordinary cement slurries from a standpoinrof'water loss, additional compositions were prepared and tested, the results of which are presented in Table IV where the effects of the composition and method of oil addition on the properties of the cement emulsion slurries are given.

applies equally to the slurries prepared by adding the cement to the emulsion of oil and water containing the calcium lignosulfonate. Where the calcium lignosulfonate is admixed with the solids, cement and bentonite, and water followed by oil added to the mixture, the amount of lignosultonate required to prevent the presence of oil in the filtrate was about 0.2% by weight based on the dry cement.

It-should be noted from the data in this table that the filtration rate of a conventional cement slurry now used in oil well cementing operations is cc. in one minute, whereas the filtration rates of slurries of our improved composition range from 16 cc. to 96 cc. in 10 minutes.

Additional slurries were prepared to show the effect 35 of the organic dispersing agent, such as calcium ligno- Table IV REFERENCE (ORDINARY NEAT CEMENT SLURRY) Composition of Emulsion Cement Slurry Filtration Water Method Fluldity-- Loss in lbs/sq. in.

0! Mix- R. P. M. at Remarks Portland Benton- Calcium ing I 400-grams Cement, ite. Ligno- Water, Oil, Stormer 3 min. 10 min. 30min.

grams grams sullonate, cc. cc.

grams 100 0 0.0 46 0- A 700 seere- 80cc.in1min.

marks EFFECT OF BENTONITE, CALCIUM LIGNOSULFONATE AND OIL 0 0. 4 70 ac A 1, 500 51 97 N0 oil in filtrate. 4 0. 0 70 20 A 460 58 8 cc. oil in cc. filtrate. 4 0. 4 70 0 A 1. 500 93 4 0. 4 70 20 A 1,000 29 57 103 N0 Oil in filtrate.

EFFECT OF CONCENTRATION OF CALCIUM LIGNOSULFONATE 4 0. 0 70 20 A 460 58 8 cc. oil in 115 cc. filtrate. 4 0. l 70 20 A 380 50 96 1 cc. oil in 119 cc. filtrate. 4 0. 2 70 20 A 920 36 70 1% N 0 011 in filtrate. 4 0. 4 70 20 A 1, 000 29 57 103 D0. 4 0. 6 70 an A l, 250 21 42 74 D0. 4 1. 0 70 20 A l, 300 12 25 46 D0.

EFFECT OF METHOD OF ADDITION 4 0.0 70 20 A 460 8 cc. oil in 115 cc. filtrate. 4 0.0 70 20 880 8 cc. oil in 137 cc. filtrate. 4 0.1 70 20 A 880 1 cc. oil in 119 cc. filtrate. 4 0.1 70 20 B 700 N 0 oil in filtrate. 4 0.6 70 20 A 1, 250 Do. 4 0. 6 70 20 C 550 D0.

l Tested in Standard A. P. I. low-pressure wall-building mud tester. I Kerosene, specific gravity of 0.80, viscosity of 1.6 centipoises.

1 A-Bentonite and calcium lignosulionate mixed with dry cement prior to addition to mix water. Oil added to above slurry. B-Emulsion of water, oil, and calcium lignosulfonatc prepared. Bentonlte mixed with dry cement and resulting mixture added to the above emulsion. of water, oil, bentonite, and calcium lignosulionate prepared. Dry cement then added to this emulsion.

It will be noted from the data in Table IV that the calcium lignosulfonate should be present in at least 0.1%

sulfonate concentration, on the thickening time of slurry and the tensile strength of the set cement at different by weight based on the dry cement in order to prevent 75 temperatures. These data are presented in Table V.

C-Emulsion Table V Composition of Emulsion Cement Blurry Tensile Strength: lbs/sq. in.

Thickening Time 1 Calcium Cured Under Cured Under Portland Cement, Bentonite, Ltlguotsui- Water, Oil, Water at120 F. Water at 180 F.

grams grams one e, cc. cc.

grams Schedule Hours Minutes No. lday 7days lday 7days 0 46 0 362 527 4 0. 4 70 20 6 1 50 4 0. 4 70 Z) 7 1 60 4 0. 4 70 2o 8 1 45 4 0.4 70 20 9 1 30 4 0. 2 70 20 8 1 10 4 0. 4 70 8 1 45 108 220 4 0. 6 70 20 8 4 200 143 4 0. 6 70 2o 9 2 00 4 0. 8 70 20 9 2 20 112 170 4 1.0 70 20 110 175 1 Tested in accordance with well simulation casing cementing jobs as per A. P. I. Code 32 (Tentative), Second Edition, June 1950:

! Kerosene, specific gravity of 0.80, viscosity of 1.0 centipoises.

From these data it may be seen that since the thickening time decreases with increasing temperature and since the addition of calcium lignosulfonate increases the thickening time, the thickening time of the cement slurry may be controlled readily by varying the amount of calcium lignosulfonate used. For low temperature wells, low concentrations in the range from 0.1% to 0.2% calcium lignosulfonate should be suflicient, whereas in deep wells with higher bottom-hole temperatures it may be desirable to raise the concentration of lignosulfonate to 0.6% or as high as 1% by weight based on the dry cement. The rate of strength development of cements increases with increasing temperature and although, as the data show, the calcium lignosulfonate decreases the rate of strength development of our cement compositions, suflicient early strengths are developed by the improved composition containing the larger amounts of the calcium lignosulfonate in the range given to regulate the thickening time at the higher temperatures. It will be noted from the data that the ultimate tensile strength of the slurries having compositions as shown in Table IV is about 200 lbs. per sq. in., which is quite desirable for well cementing purposes. Tensile strengths of to 100 lbs. per sq. in. are considered entirely adequate in this use.

To illustrate further the amount of liquid hydrocarbon to be used in our composition, the data in Table V are presented to illustrate a number of cement compositions which are made up to give cement compositions having from 10 cc. to 75 cc.of oil per 100 grams of cement, the amount of water in the composition being adjusted to maintain the fluidity of the slurries at approximately constant value. These slurries were made up by blending the calcium lignosulfonate with the dry cement, adding this mixture to the water with stirring and then adding the oil with stirring. The composition of these slurries, their fluidities, and the tensile strength after curing under water are given in Table VI.

Table VI 40 Tensile Strength, Composition of Emulsion Cement lbs./sq. in. (Cured Slurry Fluidityunder Water at R. P. M. 120 F.)

grams Portland Calcium Stormer 4o Cement, Oil, Water, Ligno- 1 day 14 days 00. cc. sulfonate,

grams 0 46 0. 0 040 421 530 10 50 0. 4 040 205 347 50 a0 0. 4 910 163 268 100 30 0. 4 910 92 172 40 0. 4 040 57 127 50 0.4 940 35 85 60 0. 4 1, 000 25 l 08 76 0. 4 040 25 i 47 1 ggtl gg s geciflc gravity oi 0.835, viscosity of 3.0 ceutipoises.

Referring to the data in Table VI, the 14-day strength of the set cement represents, for all practical purposes, the ultimate and final strength of the composition. While as little as 10 cc. of oil per 100 grams of cement caused a definite reduction in strength of the cement composition, it is to be noted that an amount above 10 cc. per

60 cc. of liquid hydrocarbon per 100 grams of cement,-

7 between 50 cc. and 100 cc. of water per 100 grams of cement, and an organic dispersing agent in the range between 0.1 gram and 1.0 gram per 100 grams of cement to give a cement composition when set having a tensile strength of 300 lbs. per sq. in. or less. Actually, it is preferred to use liquid hydrocarbon in an amount in the range between 20 cc. and 40 cc. per 100 grams of cement, water in an amount in the range from 60 cc. and 80 cc. per 100 grams of cement, and an organic dispersing agent in the range between 0.2 gram and 0.6 gram per 100 grams of cement.

In order to illustrate the effectiveness of other water soluble organic dispersing agents such as the product described in Serial No. 209,510, supra, slurries were made The data in Table VII show that the sodium salt of sulfonated phenol formaldehyde product is effective as an organic dispersing agent and compositions are produced having the desirable properties sought for.

5 In order to show that slurries containing crude oil in 1 Tested in accordance with Schedule 6, well-simulation caeing'cementing job for 10,000 it. depth, A.P.I. Code 32 (Tentative), Second Edition, June 1950.

I Kerosene specific gravity of 0.80, viscosity of 1.6 centipoises.

I Crude oil, specific gravity of 0.85, viscosity of 5.0 centipoises.

up with the sodium salt of sulfonated phenol formaldehyde condensation product in compositions in accordance with the present invention. The compositions of these slurries and the results of the tests thereon are presented inTable V11.

It will be noted from the data in Table VIII that the emulsion cement slurry prepared with crude oil is very similar in properties to that prepared from kerosene. These two slurries were prepared by emulsifying the oil, water and calcium lignin sulfonate together and then Table VII Composition of Emulsion Cement Slurry Filtration Tensile Strength,

Water Loss at Thickening 3 lbs/sq. in.-Cu.red 100 lbs/sq. in., Time Under Water at Sodium Fluidltycc. 180 F.

Salt of R. P. M. at Portland Cement, sulfonated Benton- Water, Oil, 1 400 grams grams Phen ite, grams cc. cc. Stormer Formalde- 3 min. 30min. Hrs. Min. 1 day 28 days hyde, grams I Kerosene, 0.8 Specific gravity. 1 Tested in Standard A.P.I.10W-pressure wall building mud tester.

3 Tested in accordance with Schedule 8, well-simulation casing-cementing Job for 14,000 ft. depth, A.P.I. Code 32 (Tentative),

Second Edition, June 1950.

4 Filtrate contained 3 cc. of oil.

As indicated by the results in Table VII, the sodium salt of sulfonated phenol formaldehyde condensation product is effective in preparation of oil emulsion cements of our invention. In preparing the slurries the tests of which are presented in Table VII, the sodium salt of the sulfonated phenol formaldehyde product was mixed with the dry cement and water was added to the mixture while stirring. Oil was then added with continued stirring to produce the final slurry. In the instance where bentonite was used the bentonite was mixed with the sodium salt of the sulfonated phenol formaldehyde condensation product and the dry cement.

and remarks as to the characteristics of the slurry.

Table [IL-Molecular emulsifying agents for use in oilemulsian cements 1 Filtration-A21. Fluid Loss (00.) Commercial Name of Description of Emulaliying Agent Chemical Composition Chemical ype 1 2 a Filtrate Remarks min. min. min. min.

(1) Span so Sorbitan Mono-Laurate Ester.--..--..... 1. 2. 5 3. 5 6. 5 2 cc. emulsion Cement was oil-wet;

on water set in 24 hours, but filtrate. crumbly.

(2) Pluronic L44. Condensation roduct of Eth- Ether-Alcohol... 7 9 Creamy emul- Slurry very fluid; let

ylene Oxi e, Propylene sion. in 24 hours. Oxide and Propylene Glycol. (3) Pluronle F68 do do 7 9 5 11 16 5 Cloudy Do.

emulsion. (4) BRU 835 Polygaxiyethylene Lanryl 5.1- do 9 13 18 Creamy Do.

( Rene: 30 A Polyoxyethylene Alcohol--. do 13 16. 5 18. 5 Do.

(6 Triton X-100 Polyloxyethylene Octyl Phe- .-..-do 13 17 19 Do.

(7) Igepal CA-Extra A Polyether-elcohol condensado 15 18 Do.

High Concentrate. tion product.

(8) Tween 20 Polyoxyethylene B orbitan Ether-Ester.--.- 11 14. 5 17 do Slurry very fluid; set

Iliono-Laurate. in 72 hours.

(9) Tweendl) Polyoxyethylene Sorbitan .-..-d0 12 15 18 25 ....-do Do.

Mono-Stearate.

(10) Tergitol NIX A Polyoxyethyleno Alcohol..- Ether-Aleohoi.-. 13 17 19 do 811% fluid; set o 71) Igepal Co-630. Alslr glmlg e rgo xg Polyoxyethdo v 17 21 23 do Do.

(12) Emulphor ELA.. Condensation product of Eth- Ether-Ester 12 16. 5 20 31 do D0.

ylene Oxides 6: Fatty Acids.

(13) Pluronic L412-.." Condensation roduet of Eth- Ether-Alcohol... 37 57 71 do Do.

ylene Oxl e. Propylene Oride and Propylene Gly- 00 (14) Span85 Sorbitan Trl-Oleate Ester 42 60 74 Cloud 1 No set test.

em on.

1 Cement composition: 100 grams Lone Star Normal Portland Cement; 00 cc. water; 30 cc. kerosene- 0.6 gram emulsifying agent. 3 Oil emulsion cement slurry without emulsiiylng agent: fluid 1m 130 cc. after 3 minutes.

It will be seen from these data that compounds of the ester, ether-alcohol, ether-ester type were employed with success. cerned, were obtained with the sorbitan mono-laurate which is an ester-type emulsifying agent. It will be noted that the original filtration fluid loss of the oil-emulsion cement slurry without the emulsifying agent was 130 cc.

presence of bentonitic clays and the compositions containing the emulsifying agent exhibit a tendency to foam.

Best results, as far as filtration rate is con- Foaming may suitably be controlled by-employment of suitable defoaming a ents, such as the siliconcs; high molecfilar weight monohydric and polyhydric alcohols,

such as octanol, polypropylene glycol and the organophosphates, such as tgdwmswp te, may be used.

after 3 minutes which indicates a remarkable reduction 40 Also in controlling the tendency oward foaming, this for the emulsifying agents of the present invention.

Additional slurries were made up with cation emulsifying agents using the same cement slurry as used to obtain the data reported in Table IX with the only diiference tendency may be reduced or eliminated by avoiding the entrainment of air during the mixing operation in which the composition is formed.

The emulsifying agents employed in the present inbeing that alkyl substituted ammonium salts were emvention, as stated before, may be the polar, non-ionic ployed. In Table X, which follows, the same type of data are presented for the slurries containing these latter emulsifying agents as were presented in Table IX.

compounds of high formula weight of hydrophilic and lipophilic nature. The compounds of greater hydrophilic and lipophylic nature appear to be more eflicient in our Table X .Cntionic emulsifying agent for use in oil-emulsion cements Filtration-A.1 .I.Flnid Loss (00.) Commercial Name of Chemical Composition Chemical Description of Remarks Emulsiiylng Agent Type Filtrate 1min. 2min. 3min. 736mm.

1) Eastman T-5661 Cetyl Dimeth l Eth 1 Amna 2 8 4 6.5 Cloud enmlsiom- Slurri iiui monium Bror nide. y AmglsCilgy let 222mm.

um (2) Eastman T-5650 063W] 'IEmethyl Ammonium -...do--...-. 4 5.5 7.6 12 do Do.

rom e. (3) Aquarad S So mTr i nethyl Ammonium --..-do-....-- 12 17 21 51 Creamy emulsion- Do.

or e. (4) Hyamine 1622 Para Di-isobutyl Phenory -..;.do-.---. 87 55 64 do Do.

Etho Ethyl Dlrnethyl Benzyi Ammonium Chloride Monohydrate.

i Oil-Emulsion Cement Slurry without emulsifying agent: fluid loss T130 cc. often 3 minutes. It will be seen from the data in Table X that the emul- 65 composition and method then those of lesser strength sifying agents from the type of the quaternary ammonium salts give improved results with best results being obtained with cetyl dimethyl ethyl and cetyl tri-methyl ammonium bromide.

with respect to these characteristics.

It will be seen that our improved composition has numerous advantages over conventional cement. Our improved composition has low density, low tensile In all of the results presented in Tables IX and X, it strength, improved settling characteristics, low water will be clear that a fluid cement was obtained which set within24 to 72 hours.

In employing the emulsifying agents of the present invention, a word of caution appears to be in order. For

losses and also by virtue of the oil content has lubricating properties. The density of our emulsion slurries, exemplified by the numerous examples, ranges from about 11 to approximately 12% lbs. per gallon as compared to 16 example, the emulsifying agents are not efiective in the 75 for neat cement slurries. The low density of our emulsion 13 slurries is important since the density of the conventional neat Portland cement slurry is higher than desirable for many cementing operations. Furthermore, the neat slurry of the prior art does not possess sutficient gel strength to suspend all the cement particles and settling may occur before the mass sets. The neat slurry of the prior art has a very high filtration and the set mass possesses greater strength than desirable. In our compositions the density of the slurries is suflicient to allow the slurry to be used in well cementing operations more efiiciently. Furthermore, we are able to produce low density slurries having a suificiently high tensile strength to be suitable for oil well cementing operations. It will be apparent to the skilled workman that We may vary the strength of our cement by suitably adjusting the concentration of oil in the slurry. The tensile strength of the set cements from our composition is about 200 and lower than 200 lbs. per sq. in. as compared to 600 lbs. or higher for neat cement, which makes our composition quite desirable for oil well cementing operations. Oliphant and Farris, supra, pointed out the advantages of such low strength cements. In the prior art cements, such as neat cement slurries, the solid particles settle appreciably and i this settling may result in a faulty cement job. On the t other hand, cement slurries, such as ours, show no tendency for the solids to settle on standing. As illustrated by the data, our compositions are outstanding from the standpoint of low water loss. Cement slurries in accordance with the present invention show filtration rates of approximately 100 cc. in minutes as compared to approximately 80 cc. in one minute for the prior art compositions when the two types of slurries are tested at 100 lbs. per sq. in. in the standard API low-pressure wall-building mud tester. As pointed out before, our composition has lubricating properties. It is believed that the use of emulsion cements will lubricate the Well casing and permit it to be rotated readily (1W placemcfifot cement.

l ons of the present invention achieve a beneficial result only by the presence of the several components therein. The presence of the liu' I O l the 1 densi a low filtration rate, anda low strength. The organic dmcalclum lignosulfonate, prevents separation of oil from the slurry and increases the thickening time. The water and the cement are used in proportions to provide a slurry of the desirable fluidity and a set mass of the desired strength. Thus each of the components of our composition cooperates to produce a desired result.

The nature and objects of the present invention having been completely described and illustrated, what we wish to claim as new and useful and to secure by Letters Patent is: 1. A cement composition adapted for use in well cementing operations having a density in the range from about 11 to approximatelyl2 lbs. per gallon and having a tensile strength when set below 300 lbs. per sq. in. which consists of a Portland cement, a liquid hydrocarbon selected from the class consisting of pure hydrocarbons and hydrocarbon mixtures having a viscosity at 100 F. less than 40 centipoises in an amount in the range between 15 14 cc. and 60 cc. per 100 grams of the dry cement, cetyl dimethyl ethyl ammonium bromide in an amount in the range between 0.1% and 1.0% by weight based on the dry cement, and water in an amount in the range between and 100% by weight based on the dry cement.

2. A cement composition adapted for use in well cementing operations having a density in the range from about 11 to approximately 12 /2 lbs. per gallon and having a tensile strength when set below 300 lbs. per sq. in. which consists of a Portland cement, a liquid hydrocarbon selected from the class consisting of pure hydrocarbons and hydrocarbon mixtures having a viscosity at 100 P. less than 40 centipoises in an amount in the range between 15 cc. and cc. per grams of the dry cement, an emulsifying agent selected from the glass consisting of the czwwgbstituted quaternary ammonium a 1 es in an amount 11 ther'airige between 0.1% and 1.0% by weight based on the dry cement, and water in an amount in the range between 50% and 100% by weight based on the dry cement suflicient to provide a pumpable slurry.

3. A cement composition adapted for use in well cementing operations having a density in the range from about 11 to approximately 12 /2 lbs. per gallon and having a tensile strength when set below 300 lbs. per sq. in. which consists of a Portland cement, a liquid hydrocarbon selected from the class consisting of pure hydrocarbons and hydrocarbon mixtures having a viscosity at 100 P. less than 40 centipoises in an amount in the range between 15 cc. and 60 cc. per 100 grams of the dry cement, cetyl trimethyl ammonium bromide in an amount in the range between 0.1% and 1.0% by weight based on the dry cement and water in an amount in the range between 50% and 100% by weight based on the dry cement 4. A composition in accordance with claim 2 in which the emulsifying agent is cetyl dimethyl ammonium bromide.

5. A composition in accordance with claim 2 in which the emulsifying agent is soy trimethyl ammonium chloride.

6. A composition in accordance with claim 2 in which the emulsifying agent is para diisobutyl phenoxy ethoxy ethyl dimethyl benzyl ammonium chloride monohydrate.

7. A composition in accordance with claim 2 in which the hydrocarbon is kerosene.

8. A composition in accordance with claim 2 in which the hydrocarbon is crude petroleum.

9. A composition in accordance with claim 2 in which the hydrocarbon is diesel oil.

10. A composition in accordance with claim 2 in which the hydrocarbon is gasoline.

11. A composition in accordance with claim 2 in which the hydrocarbon is fuel oil.

References Cited in the file of this patent UNITED STATES PATENTS 1,109,120 Ellis Sept. 1, 1914 1,599,903 Lord Sept. 14, 1926 2,054,257 Hueter Sept. 15, 1936 2,285,302 Paterson June 2, 1942 2,582,459 Salathiel Jan. 15, 1952 2,644,771 Kempthorne July 7, 1953 

1. A METHOD FOR DETERMINING THE GEOPHISCAL PROPERABOUT 11 TO APPROXIMATELY 121/2 LBS. PER GALLON AND HAVING TIES OF SELECTED PORTIONS OF UNDERGROUND GEOLOGICAL A TENSILE STRENGTH WHEN SET BELOW 300 LBS. PER SQ. IN. FORMATIONS WHICH COMPRIES MAINTAINING AT LEAST TWO WHICH CONSISTS OF A PORTLAND CEMENT, A LIQUID HYDROSPACED ELECTRODES IN CONTACT WITH A SELECTED PORTION OF CARBON SELECTED FROM THE CLASS CONSISTING OF PURE HYDROTHE EARTH, IMPRESSING A VOLTAGE DIFFERENCE BETWEEN SAID CARBONS AND HYDROCARBON MIXTURES HAVING A VISCOSITY AT ELECTRODES SO AS TO INDUCE A MAINTAIN AN ELECTRIC CUR100*F. LESS THAN 40 CENTIPOISES IN AN AMOUNT IN THE RENT FLOW THEREBETWEEN THROUGH SAID SELECTED PORTION OF RANGE BETWEEN 15 CC. AND 60 CC. PER 100 GRAMS OF THE SAID GELOFICAL FORMATIONS UNDER CONDITIONS WHICH DRY CEMENT, AN EMULSIFYING AGENT SELECTED FROM THE CLASS OTHERWISE PRODUCT SUBSTANTIAL ADVERSE POLARIZATION OFCONSISTING OF THE CALCIUM TOLERANT CATION ALKYL SUBSTITUTED FECTS AT THE SURFACE OF SAID ELECTRODES, MEASURING AND REQUATERNARY AMMONIUM HALIDES IN AN AMOUNT IN THE RANGE CORDING ELECTRICAL EFFECTS OF SAID CURRENT FLOW AS CHARBETWEEN 0.1% AND 1.0% BY WEIGHT BASED ON THE DRY CEACTERISTIC OF THE NATURE OF SAID PORTION OF GEOLOGICAL MENT, AND WATER IN AN AMOUNT IN THE RANGE BETWEEN 50% FORMATION, AND ELIMINATING INTERFERENCE OF GAS AND IRON AND 100% BY WEIGHT BASED ON THE DRY CEMENT SUFFICIENT DEPLETION POLARIZATION WITH THE MEASURED ELECTRICAL EFTO PROVIDE A PUMPABLE SLURRY. FECTS OF SAID CURRENT FLOW BY HE STEP OF MAINTAINING A FIELD OF RADIOCTIVE RADIATION AT AT LEAST ONE OF SAID THE MATERIAL IMEDIATELY ADJACENT SAID ELECTRODE.
 2. A CEMENT COMPOSITION ADAPTED FOR USE IN WELL 